Packet Routing Messages RTM_* additions

[cocobean]

Add new routing messages for better networking compatibility with FreeBSD 12 and higher. Improves routing information database, which is used in selecting the appropriate network interface when transmitting packets.

#define	RTM_CHANGE	0x3    /* Change Metrics, Flags, or Gateway */
#define	RTM_LOSING	0x5    /* Kernel Suspects Partitioning */
#define	RTM_REDIRECT	0x6    /* Told to use different route */
#define	RTM_MISS	0x7    /* Lookup failed on this address */
#define	RTM_LOCK	0x8    /* fix specified metrics */
#define	RTM_RESOLVE	0xb    /* request to resolve dst to LL addr - unused */
#define	RTM_NEWADDR	0xc    /* address being added to iface */
#define	RTM_DELADDR	0xd    /* address being removed from iface */
#define	RTM_IFINFO	0xe    /* iface going up/down etc. */
#define	RTM_NEWMADDR	0xf    /* mcast group membership being added to if */
#define	RTM_DELMADDR	0x10   /* mcast group membership being deleted */
#define	RTM_IFANNOUNCE	0x11   /* iface arrival/departure */
#define	RTM_IEEE80211	0x12   /* IEEE80211 wireless event */

[cocobean]

Additional route utility commands:

     flush	 Remove all routes.
     change	 Change aspects of a route (such as its gateway).
     monitor	 Continuously report any changes to the routing information base, routing lookup misses, or suspected network partitionings.